LOS ANGELES (AFP) - James Cameron doesn't have many regrets -- after all, he has now directed three of the four highest-grossing films of all time.

But if he could go back and remake "Titanic," the film that started his record streak 25 years ago and is being re-released in theaters Friday, there is one thing he would change.

"Based on what I know today, I would have made the raft smaller, so there's no doubt!" said Cameron.

Such is the film's enduring popularity, even a quarter of a century later debates and theories continue to swirl around the fate of Leonardo DiCaprio's lead character.

Fans insist Jack could have survived the icy Atlantic waters after the ocean liner sank, if only he had shared an improvised raft with Kate Winslet's Rose.

Instead, Jack gallantly gave Rose an entire wooden door to float on, condemning himself to a freezing death but ensuring she survived.

It is just one example of how the story of the Titanic "never seems to end for people," Cameron told a press conference held for the anniversary re-release.

"There have been much greater tragedies since the Titanic -- I mean, World War One, tens of millions of people died. World War Two..."

"But the Titanic has this kind of enduring, almost mythic, novelistic quality. And it has to do with, I think, love and sacrifice and mortality.

"The men who stepped back from the lifeboats so that the women and the children could survive."

- 'Final verdict' -

Cameron put Jack's individual sacrifice to the test in a new National Geographic documentary, running experiments featuring two stunt performers and an exact replica of the film's door in a cold water tank.

In "Titanic: 25 Years Later with James Cameron," the stunt actors were fitted with internal thermometers to chart how quickly their bodies plunged toward hypothermia.

While the first test confirmed Jack would have died if he had acted according to the film's plot, a second found the pair could have both balanced on the door and kept their upper bodies out of the water. 

"He got into a place where if we projected that out, he just might have made it until the lifeboat got there," admitted Cameron.

"Final verdict? Jack might have lived. But there's a lot of variables."

- Epic love story -

"Titanic" was first released in December 1997, and held the number one box office spot for 15 consecutive weekends.

While today most films earn their biggest profits on opening weekend, "Titanic" peaked on its eighth weekend -- Valentine's Day.

The epic love story is now being re-released ahead of this year's Valentine's Day weekend, where it will hope to add to its $2.2 billion total haul.

"I'll grant you $100 million of our box office (was) for Leonardo DiCaprio's appeal to 14-year-old," girls, joked Cameron.

"Titanic" is currently behind only "Avengers: Endgame" and Cameron's "Avatar," but is expected to soon be surpassed by "Avatar: The Way of Water" -- again, by Cameron -- which has made $2.18 billion and is still drawing crowds.

Collectively, Cameron's three monster hits have collected $7.25 billion -- roughly the entire annual GDP of Bermuda.

Besides making him an extraordinarily wealthy man, the three-hour-long "Titanic" has left another important if divisive legacy.

"Historically before 'Titanic,' the wisdom -- which proved not to be true -- was that a long movie can't make money," said Cameron.

The first "Avatar" ran for 162 minutes and again "people said they wanted more," he said.

"We took that to heart and we made a three-hour-and-12-minute movie for the new 'Avatar.' "And it's doing very well."